Secondly I think the fact that the phrase fails to capture
either the original usage or the historical situation it
came out of is a natural part of how language evolves.
Phrases come into use, and seldom do people remember the
original circumstances, and seldom does a widely used
phrase remain static in meaning. Indeed after time its
original meaning becomes far less relevant than the
agreed upon, shared meaning.

For a random instance, we all know what it means to
welsh on a bet. I have seen the phrase used, you will
find it in the dictionary, etc. And almost never is it
used with the intention of furthering a racial
stereotype...because that isn't the meaning we continue
to share.